I honestly recommend going to the DMT-nexus and asking there as you will find better answers on not just how much to smoke, but very cheap and effective methods of smoking it. You should also ask about changa as that is a way to prepare leaf that could be weighed out at 0.01 for an effective dose. Over here no one can really give you recommendations as it could lead to your harm unless they literally write out an essay on what to do with it. There is also a device dubbed "the time machine" used to vaporize pure DMT. Again I just recommend going there not just to get recommendations, but to take time into researching this fascinating compound before hopping into it as it will help make sure you get the experience you desire as the molecule appreciates you showing respect in understand what you are doing.
Really that is all the advice that I, or even anyone else can really give you. Once you feel you are ready you will be and that will not happen until you have faith you are doing things the right thing, but that will only happen when you are comfortable with what you know being sufficient to doing what you need to get done right.
I am being kind of vague, but I hope this helps.
Edit: Wait... I thought you extracted it..... If he told you one hit than trust him as he probably is not going to screw you over. I recommend getting a bubbler and some kind of herb (cannabis is my first choice, but if you can not get that go to a bulk herb store and get mullien or some other leaf). Throw the herb into a bowl with some dmt and than put some more on top to sandwich it. When you smoke it do not bathe it in fire, but hold it further away and just suck in the heat and hold your hit in for at least 30 seconds as it takes a long time to absorb. I recommend preparing a space to lay down as you will be in a deep trip for a minute.
Do not try making changa out of one hit as it will be a waste... Sandwiching it in a bowl is good enough. I do not recommend trying to vape it purely as it is very easy to overheat the spice, which in my experience ALWAYS causes a very harsh smoke, horrid physical feeling, and bad trip.